Chair with elastically-deformable seat and backrest

ABSTRACT

A chair comprising: a metal frame formed by a plurality of tubular metal elements, including a seat portion having two tubular seat support elements and a backrest portion having two tubular backrest support elements extending upwardly from the seat portion, a flexible seat panel of plastic material with high elasticity, having two lateral tubular portions into which respective tubular seat support elements are inserted, and a flexible backrest panel of plastic material with high elasticity having two lateral tubular portions into which respective tubular backrest support elements are inserted, wherein in a rest condition there is a transverse clearance between the outer edges of the lateral tubular portions of the flexible seat panel and of the flexible backrest panel and the respective tubular support elements, and wherein in a deformed condition said transverse clearance is reduced to zero.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of Italian patent application number TO2014A001007, filed Dec. 4, 2014, which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a chair with elastically-deformable seat and backrest.

In particular, the invention relates to a chair having a metal frame formed by bent tubular elements that carry a seat panel and a backrest panel.

2. Description of Prior Art

As is well known in the field, to increase the comfort, the seat and the backrest should adapt to the weight of the user and to the backward thrust applied by the user's back.

One method for adapting the geometry of the chair to the weight of the user and to the backward thrust applied to the backrest envisages the use of “weight-activated” mechanisms with tilting and mutually-synchronized seat and backrest.

A simpler and cheaper way to adapt the geometry of the chair to the weight of the user and to the backward thrust applied on the backrest is that of producing the seat and the backrest by means of deformable elastic elements, for example, sheets of fabric stretched on lateral supports of the seat and the backrest. These solutions are generally affected by a limited possibility of elastic deformation of the sheets forming the seat and the back.

SUMMARY OF THE INVENTION

The present invention aims to provide a chair with a simple structure, characterized by a wide adaptability of the support surfaces of the seat and the backrest.

According to the present invention, this object is achieved by a chair having the characteristics forming the subject of claim 1.

The claims form an integral part of the disclosure provided here in relation to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in detail with reference to the attached drawings, given purely by way of non-limiting example, wherein:

FIG. 1 is a front elevational view of an embodiment of a chair according to the present invention.

FIG. 2 is a cross-section according to the line II-II of FIG. 1.

FIG. 3 is a cross-section of the part indicated with the arrow III in FIG. 2, illustrating the seat in the deformed position.

FIGS. 4 and 5 are cross-sections according to the arrows IV and V of FIGS. 2 and 3, illustrating the seat in the rest position and in the deformed position.

FIGS. 6 and 7 are enlarged details of the parts indicated by the arrows VI and VII in FIGS. 4 and 5.

FIG. 8 is a perspective view of the backrest indicated by the arrow VIII in FIG. 1.

FIG. 9 is a cross-section on an enlarged scale of the part indicated by the arrow IX in FIG. 1.

FIGS. 10 and 11 are cross-sections according to line X-X of FIG. 1 in the rest position and in the deformed position, respectively.

DETAILED DESCRIPTION

With reference to FIGS. 1 and 2, numeral 10 indicates a chair according to a first embodiment of the present invention. The chair 10 comprises a metal frame 12 formed of bent tubular metal elements. The frame 12 includes a seat portion 14 and a backrest portion 16. The seat portion 14 of the frame 12 comprises two tubular seat support elements 18 oriented longitudinally and parallel to each other along opposite lateral sides of the chair 10. The backrest portion 16 of the frame 12 comprises two tubular backrest support elements 20 parallel to each other and extending upwardly from the seat portion 14. The tubular backrest support elements 20 are located on opposite lateral sides of the chair 10.

The frame 12 of the chair 10 comprises two front leg elements 22 connected to the front ends of the respective tubular seat support elements 18. The lower ends of the front leg elements are connected to the front ends of the respective lower longitudinal elements 24. The rear ends of the lower longitudinal elements 24 are connected to lower ends of the respective rear leg elements 26. The tubular backrest support elements 20 are formed by upward extensions of the respective rear leg elements 26. Preferably, the tubular seat support element 18, the front leg element 22, the lower longitudinal element 24, the rear leg element 26 and the tubular backrest support element 20 on each side of the chair 10 are formed by a single bent tubular metal element. The rear end of each tubular seat support element 18 is fixed to the lower end of the respective tubular backrest support element 20, coinciding with the upper end of the respective rear leg element 26.

The two tubular backrest support elements 20 are fixed to respective ends of a rear cross member 28. The front leg elements 22 are fixed to respective ends of a front cross member 30.

The chair 10 comprises a flexible seat panel 32 and a flexible backrest panel 34 formed of molded plastic material with high elasticity. The flexible seat panel 32 and the flexible backrest panel 34 are capable of elastically deforming according to an arcuate shape and of returning to the initial shape when the force causing the deformation ceases. Suitable materials are, for example, nylon and polyoxymethylene (POM).

The flexible seat panel 32 and the flexible backrest panel 34 have respective lateral tubular portions 36, 38, integrally formed with the respective panels 32, 34. The tubular seat support elements 18 extend through the lateral tubular portions 36 of the flexible seat panel 32. The tubular backrest support elements 20 have respective upper ends inserted within respective lateral tubular portions 38 of the flexible backrest panel 34.

With reference to FIGS. 2 to 5, in rest conditions, the flexible seat panel 32 has an essentially flat shape. With reference to FIGS. 4 and 6, in rest conditions, in each lateral tubular portion 36 of the flexible seat panel 32 there is a clearance Ps in a transverse direction between the tubular element 18 and the outer edge of the corresponding lateral tubular portion 36.

When a user is sitting on the flexible seat panel 32, the flexible seat panel 32 assumes an arcuate shape as shown in FIGS. 3 and 5. The flexible seat panel 32 is elastically deformed to assume the arcuate position. During the elastic deformation of the flexible seat panel 32, the respective lateral tubular portions 36 move in a direction transverse to the respective tubular support elements 18, by an amount equal to the respective transverse clearance Ps. In the deformed position of the flexible seat panel 32, the clearance Ps between the outer edges of the tubular portions 36 and the respective tubular support elements 18 is canceled. When the ends of the lateral tubular portions 36 come into contact with the respective tubular elements 18, a further deformation of the flexible seat panel 32 is prevented. The clearance Ps between the outer ends of the lateral tubular portions 36 and the respective tubular elements 18 determines the maximum deformation Ds of the flexible seat panel 32.

FIGS. 6 and 7 show the detail of the relative movement of the lateral tubular portions 36 with respect to the tubular seat support elements 18, in the rest position and in the deformed position of the flexible seat panel 32.

When the user rises from the chair 10, the flexible seat panel 32 returns to the undeformed configuration as a result of its elasticity. The lateral tubular portions 36 return to the position illustrated in FIG. 6 and the lateral clearance Ps returns to the initial value.

In the illustrated example, the clearance Ps of the lateral tubular portions 36 is essentially constant along the longitudinal axis of the respective tubular seat support element 18. Consequently, the maximum deformation Ds of the flexible seat panel 32 is essentially constant along the central axis of the flexible seat panel 32.

Alternatively, the clearance Ps, the ends of the lateral tubular portions 36 and the respective tubular elements 18 could vary along the axis of the respective tubular element 18, from a minimum value level with the front end of the flexible seat panel 32, and a maximum value level with the rear end of the flexible seat panel 32. In this way, in the conditions of use, the deformation of the seat panel has a minimum value at the front edge of the seat panel 32 and a maximum value at the rear edge of the seat panel 32. Thus, in the deformed position, the central axis of the seat panel 32 inclines backwards with respect to the undeformed position. The backward inclination of the flexible seat panel 32 has a similar effect to that of chairs with seats hinged to the fixed structure about a transverse axis.

With reference to FIGS. 8-11, the flexible backrest panel 34 has a lower edge 40 and an upper edge 42. In the example shown, the lateral tubular portions 38 of the flexible backrest panel 34 have lower ends aligned with the lower edge 40 and upper ends located lower than the upper edge 42. Two notches 44 curving inwardly from the respective outer edges of the flexible backrest panel 34 are arranged immediately above the upper ends of the lateral tubular portions 38. The flexible backrest panel is preferably provided with vertical ribs 46 parallel to each other and protruding from the front surface of the flexible backrest panel 34.

The lateral tubular portions 38 of the flexible backrest panel 34 have transverse through-cuts 48 spaced apart in the vertical direction. Each cut 48 forms an empty space in the wall of the respective lateral tubular portion 38, contained in a plane orthogonal to the longitudinal axis of the respective lateral tubular portion 38. The through-cuts converge on respective through-holes 50 formed along the inner edges of the respective lateral tubular portions 38.

With reference to FIG. 10, in the rest condition, a clearance Pb in a transverse direction is provided between the outer edges of the lateral tubular portions 38 of the flexible backrest panel 34 and the respective lateral tubular elements 20.

With reference to FIG. 9, the transverse clearance Pb of the lateral tubular portions 38 varies along a vertical direction, from a minimum value Pb′ level with the lower edge 40 of the flexible backrest panel 34, to a maximum value Pb″ level with the upper edge of the lateral tubular portion 38.

In the rest condition (FIG. 10), the flexible backrest panel has an arcuate shape. When a user leans back against the flexible backrest panel, it is elastically deformed, as shown in FIG. 11. The radius of curvature of the flexible backrest panel decreases. During the elastic deformation of the flexible backrest panel 34, the respective lateral tubular portions 38 move in a transverse direction with respect to the respective tubular support elements 18, by an amount equal to the respective transverse clearance Pb. In the deformed position of the flexible seat panel 32, the clearance Pb between the outer edges of the tubular portions 38 and the respective tubular support elements 20 is canceled, as shown in FIG. 11. When the outer edges of the lateral tubular portions 38 come into contact with the respective tubular elements 20, a further deformation of the flexible backrest panel 34 is prevented. The clearance Pb between the outer edges of the lateral tubular portions 38 and the respective tubular elements 20 determines the maximum deformation of the flexible backrest panel 34. Given that the clearance Pb varies in the vertical direction, the maximum deformation of the flexible backrest panel 38 is greater for areas closest to the upper edge 42 and lower for areas closest to the lower edge 40. Consequently, in the deformed position, the backrest inclines backwards with respect to the rest position by an angle a, as shown in FIG. 2, where the continuous line indicates the rest position and the dotted line indicates the deformed position of the flexible backrest panel. The backward inclination of the backrest has a similar effect to that of chairs with tilting backrests articulated about a transverse axis. The through-cuts 48 serve to enable a differentiated deformation of the various transversal portions of the flexible backrest panel.

The flexible backrest panel is subject to an elastic return force which tends to return it to the undeformed position. This elastic force applies a thrust on the back of the user, in a manner similar to the elastic mechanisms of chairs with tilting seats. When the backward thrust applied by the user ceases, the backrest returns to its rest position illustrated in FIG. 10.

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments can be widely varied with respect to those described and illustrated, without thereby departing from the scope of the invention as defined by the claims that follow. 

1. A chair comprising: a metal frame formed by a plurality of tubular metal elements, including a seat portion having two tubular seat support elements and a backrest portion having two tubular backrest support elements extending upwardly from the seat portion; a flexible seat panel of plastic material with high elasticity, having two lateral tubular portions into which respective tubular seat support elements are inserted; and a flexible backrest panel of plastic material with high elasticity having two lateral tubular portions into which respective tubular backrest support elements are inserted, wherein, in a rest condition, there is a transverse clearance between the outer edges of the lateral tubular portions of the flexible seat panel and of the flexible backrest panel and the respective tubular support elements and wherein, in a deformed condition, said transverse clearance is reduced to zero.
 2. A chair according to claim 1, wherein in the rest condition, said transverse clearance of the lateral tubular portions of the flexible seat panel has a constant value along a longitudinal axis of the respective tubular seat support element.
 3. A chair according to claim 1, wherein in the rest condition, said transverse clearance varies along a longitudinal axis of the respective tubular seat support element from a minimum value at a front edge of the flexible seat panel to a maximum value at a rear edge of the flexible seat panel.
 4. A chair according to claim 1, wherein in the rest condition, said transverse clearance of the lateral tubular portions of the flexible backrest panel varies in the vertical direction from a minimum value at the lower ends of the lateral tubular portions to a maximum value at the upper ends of the lateral tubular portions of the flexible backrest panel.
 5. A chair according to claim 4, wherein the lateral tubular portions of the flexible backrest panel are provided with through-cuts spaced apart in the vertical direction.
 6. A chair according to claim 1, wherein said frame comprises two front leg elements having upper ends connected to respective front ends of the tubular seat support elements and two rear leg elements forming a downward extension of the respective tubular backrest support elements, wherein the lower ends of the front leg elements and the rear leg elements are interconnected by means of respective lower longitudinal elements.
 7. A chair according to claim 6, wherein the tubular backrest support elements are fixed to respective lateral ends of a rear cross member.
 8. A chair according to claim 6, wherein said front leg elements are fixed to respective lateral ends of a front cross member. 